Increasing Power of an Air Rifle

[soul]

Worthy attempt, will need many trials to get there ...

Firstly improving sealant should be already attempted by the manufacturers world over, it will demand its own trials, material and a long haul.

The other aspect of improving pressure, changing the dimensions, spring material will be both time consuming and expensive.

I seriously doubt a DIY approach will make any dent, it will be more like investing and developing a new product. But certainly eager to see how it goes, all the best.

[brihacharan]

We have heard enough "About Increasing the Power in an Air Rifle".....
Pray do let an 'ignoramus' like me know - as to what does "POWER" exactly mean?

Briha

[aadhaulya]

Worthy attempt, will need many trials to get there ...

Firstly improving sealant should be already attempted by the manufacturers world over, it will demand its own trials, material and a long haul.

The other aspect of improving pressure, changing the dimensions, spring material will be both time consuming and expensive.

I seriously doubt a DIY approach will make any dent, it will be more like investing and developing a new product. But certainly eager to see how it goes, all the best.

Thanks for the encouragement. I know that this is not a regular DIY project. First I have to understand the performance parameters of an AR. For that I will plan to generate some data like muzzle velocity with a pellet of various masses. Then after measuring the bore, stroke of piston etc. Then holes would be cut in the cylinder to fix pressure gauge and other measuring tools as I will decide over the course of time. Off course it is going to be expensive considering that I may not succeed.

We have heard enough "About Increasing the Power in an Air Rifle".....
Pray do let an 'ignoramus' like me know - as to what does "POWER" exactly mean?

Briha

Briha ji, What I mean by power is energy of the pellet in 'joules' and since the mass of the pellet will remain more or less the same I would have to increase the velocity of the pellet as it leaves the barrel. Also as mentioned by GBM the accuracy would be compromised as the rifling in the barrel would have to match the higher speed and the pellets also are also probably designed for lower speeds. But I do not have the capability or equipment for designing and creating new rifling or pellets to suit my requirement.

Regards

[brihacharan]

Faster Isn't Always Better
Why Muzzle Energy Is an Important Factor in Air Rifle Shooting

An extract from an article ref: http://www.airgundepot.com/faster-isnt-better.html

The air gun industry is notorious for touting the FPS (feet per second) of their air guns. When we first started Air gun Depot back in 2002 1000 FPS was the standard for spring powered air rifles. Now we are seeing manufacturers tout speeds up to 1600 FPS. It seems like every year we see the FPS of air rifles on the rise. The manufacturers are "keeping up with the Jones'" so to speak, each one trying to outdo the other. Hey, even we get caught up with the high FPS numbers and use them in our advertising for certain air rifle models. While there is no doubt that air rifles are getting more powerful as new technologies come on board, FPS isn't all that it's cracked up to be.

First off, manufacturers use very light alloy pellets when they chrony their air rifle models. Also, some manufacturers will use the age old trick of dieseling to reach their FPS claims. If you don't know already, dieseling occurs when you put a tiny drop of a flammable substance such as diesel fuel in the hollow part of the pellet skirt. When the supercharged hot gas released by the air gun comes in contact with the pellet a tiny explosion occurs giving the pellet some extra juice.
You can forget about accuracy when doing this and your air gun will probably die a fast death if you did this with every shot so we don't recommend it.

So let’s take a look at why FPS should not solely be used to judge the quality / effectiveness of an air rifle. As mentioned above high FPS numbers in spring powered air rifles can only be attained by using light alloy pellets, the dieseling effect, or a combination of both. You may notice that when you fire a break barrel air rifle rated at 1200 FPS or above with light alloy pellets you will hear a loud crack. This crack is the pellet breaking the sound barrier. The speed of sound is around 1100 FPS (it varies with altitude and temperature).
When a light alloy pellet is fired through a magnum air rile it breaks the sound barrel as soon as it leaves the barrel. This means that the shock wave that is created will be behind the pellet. However, the pellet doesn't stay supersonic for long and when it goes sub sonic that shock wave catches up to the pellet and can cause the pellet to tumble. This greatly affects accuracy and therefore will affect your groupings.

Now let's take a look at FPS associated with hunting applications. This is where muzzle energy comes into play. The definition of muzzle energy is as follows: the amount of energy a projectile contains measured as soon as it leaves the barrel. The formula for muzzle energy is pellet weight X FPS X FPS / 450240 = Ft.lbs of Energy (F.P.E) For example, a .177 cal 4.7 grain alloy pellet traveling at 1400 FPS (Energy= 20 ft. lbs) will have a lot less knockdown power than a .22 cal 14.3 grain pellet traveling at 1000 FPS (Energy= 32 ft lbs) So in simplistic terms, the higher the Ft. Lbs of Energy the more knock down power a pellet will have when it hits a target. Basically a heavier pellet traveling at a slower velocity will almost always have a higher F.P.E. than a very light pellet traveling at high FPS.

Remember, F.P.E is calculated as soon as it leaves the barrel and then gravity and friction take over slowing the pellet down the further it gets from the muzzle of the gun that fired it. Heavier pellets will also retain more of their energy down range. For example if you have a 14.3 grain .22 cal pellet at 850 FPS and a 12.7 grain .22 cal pellet shooting at 925 FPS both have similar F.P.E when fired but the heavier pellet will have almost 2 times the knock down power at 60 yards than the lighter pellet will because it retains more of its energy during flight.

In conclusion, you should always consider the muzzle velocity of your air rifle and not solely rely on how fast your air gun shoots. You should always select different types of pellets for your air gun and do your own testing. It's important to find the pellet that your air rifle likes the best.

As always, have fun and shoot safely.
Briha

[aadhaulya]

I have run into my first issue during the designing stage itself.

Brihaji,
You have given a good input and helped me a lot. The first road block also developed after going through your post as follows.
1. I had not intended any sort of chamber detonation or dieseling. As these create an instant increase in pressure increasing the fpr.
2. My plan was to increase the pressure for a springer, consistently and consistently so that the results are about the same on every shot. That could not be achieved by detonation of any sort.
3. I have access to the commercially available Indian Pellets or even maybe imported ones so that I have no difference in the design and weight of each pellet, for recording the results.

Now the problem that I anticipate is as follows.
What ever pressure that I am able to generate in the normal course may not help much as the pellet will leave the seat at the designed pressure. That is why detonation is helpful as it generates the pressure instantly (before the pellet has a chance to leave its seat).
But since I am not taking that route, I have to go into more precise calculations for the pressure required so that the pellet continues to gain speed even after leaving the seat, till it exits the barrel.

Therefore, my requirements of the gun also change slightly.
1. Fixed barrel, under lever loading springer.
2. Most important is the maximum barrel length that I can get.

I can proceed with my designing only after I have the total inner volume of the barrel (depending on the exact lenght of the barrel). This is the basic requirement to calculate the pressure I need to develop.
Last stage would be finding a method to develop that pressure (I feel that this part would be the simplest). I only hope my funds last out to finish the project as the testing equipment and modification is going to cost me a lot of money.

Regards

Atul

[Commonwealth_of_PA]

From the original post by aadhaulya, just a point of clarification

E=mc^2 is the mass energy relationship of relativity. According to Einstein. How much energy you get when you convert matter directly into energy (e.g. nuclear mass defect deficit) and vice versa.

E= Energy
m= mass
c = The speed of light, which is constant

I believe you were thinking of:

K = 1/2mv^2 where

K= Kinetic energy
m= mass
v = velocity (NOT constant)

I believe the similarity between the two equations is coincidental but since I have never derived the one Einstein came up with ( ) I don't know for sure.

How does a spring and piston AR work? I don't know so maybe you can help. Does the compressed spring release when you pull the trigger, causing the air in the cylinder to compress at the instant of firing?

[aadhaulya]

I believe the similarity between the two equations is coincidental but since I have never derived the one Einstein came up with ( ) I don't know for sure.

The similarity is not coincidental. The basic formula has to remain the same, though I somehow I got confused in the beginning.

How does a spring and piston AR work? I don't know so maybe you can help. Does the compressed spring release when you pull the trigger, causing the air in the cylinder to compress at the instant of firing?

In a spring operated AR the spring and piston are pushed back to the locking position by depressing the barrel or a liver. The pellet is then loaded in the barrel and the base of the pellet seals the barrel from the action.
When the trigger is pulled it releases the drawn piston and spring behind it. The piston is pushed by the spring towards the pellet sitting in the barrel. The air gets compressed and the pressure on the pellet increases suddenly.
At a particular pressure depending on the design and material used for the pellet it leaves the seating and travels down the barrel at about 1000 fps.

Hope I am clear enough in my explanation.

Regards

Atul

[brihacharan]

After going through all the posts an inner voice started to cry out Loud
With due respect to the original inventors of the AR....
Please "Tune your ARs" to shoot smooth & vibration free with 'accuracy' in mind ----"Increase in Power" will automatically follow....However Minimal
And that would be a BONUS!!!!
Briha

[pratik_mahale]

power and accuracy in a springer are diametrically opposed

[Basu]

I completely agree with you....Pratik..
aadhaulya has rejected my proposal of controlled detonation , inspired by Cardrew.
I am keenly watching his research .
A smaller barrel can help to cut short the decelaration of pellet while exiting.

Basu

[aadhaulya]

Basu,

I had rejected the idea of detonation as it has already been tried. I want to attempt something new. Instead of shortening the barrel I want to have a long barrel and generate enough pressure so that the pellet continues to accelerate as long as it is in the barrel.

aadhaulya has rejected my proposal of controlled detonation , inspired by Cardrew.

Basu

May be some day you may also quote, 'Inspired by IFGian Atul" instead of 'Cardrew'
If I succeed off course, other wise a lot of time, effort and most important money goes down the drain.

Regards

Atul

[sa_ali]

After going through all the posts an inner voice started to cry out Loud
With due respect to the original inventors of the AR....
Please "Tune your ARs" to shoot smooth & vibration free with 'accuracy' in mind ----"Increase in Power" will automatically follow....However Minimal
And that would be a BONUS!!!!
Briha

I am no guru, but i did tune my air gun IHP 25 with Jim maccari spring, I did all that i learned from the gurus here, went crazy finding molebendum greese, silicon oil, place to give mirror finish, etc, my parents got angry with me as i was focusing more on airgun than job .

In the whole process, i was getting impatient as i was loosing lot of time and energy, being an IT guy, job hardly leaves you with time. I ended up actually off setting up my barrel, which i then had to get straight and i am still yet to cal liberate the sight again, almost broke the cocking arm, its now wielded. In all this i did get gun with big kick of recoil, and viberation, which resulted in 1 of the 2 side screw needing re-threading. The trigger needs rework also now as its not able to handle the pressure effectively. I ended up creating a monster . I miss my old smooth IHP 25 which was easy and fun to shoot. the gun is pretty much lying most of the time.

So to summarize, I would recommend, follow the golden rule of having decent powered airgun which is fun to shoot and good at handling. just a thought

[aadhaulya]

sa_ali,

Thanks for your and every ones suggestions. I also agree that I need a good decent gun to play around with. But I already have two of them that are about 2 to 5 years old. But I would have fired, maybe about a total 50 shots between the two of them. As per what I have learnt here that you need to fire off about 100 to 500 shots before trying to tune it. Therefor, that is a different story.
The 'Power Increase' I am talking about is a new gun which gives me supersonic speed (more that 1200 fps) with a heavy pellet. Though, I have worked out my source of power, but this experiment now requires funds that will take me a few months to save up (thanks to the recession in business for the last couple of years in India).
After I have tested and documented the results, this gun will also go into the gun cabinet like the other AR's.
For regular use if my interest persists in AR's I will go in for semi auto CO2 AR's only.

Regards

Atul

[sa_ali]

Would love to see your experiment and the result. Be lil carefull as would be already reading about the arms act, all these things can easily law in gunsmith category as per police , technically speaking any screw driver using person can also be called as gun smith.

[aadhaulya]

Would love to see your experiment and the result. Be lil carefull as would be already reading about the arms act, all these things can easily law in gunsmith category as per police , technically speaking any screw driver using person can also be called as gun smith.

As of now the AR's are not covered under the arms act. But if you are not trying to pull my leg, this could be a serious issue. Then you are not able to tinker or tune your AR's. Besides would dis assembly of pistols, guns etc. for maintenance, cleaning and lubrication would also qualify as a gunsmiths job.

I wonder if any one has an idea of this aspect legally.

Regards

Atul